The present invention relates to homopolymers and copolymers containing pendant hindered amine groups which are useful as light and heat stabilizers for organic materials and to stabilized compositions containing said copolymers.
The hindered amine compounds having the 2,2,6,6-tetra-substituted piperidinyl structure have long been known as effective light stabilizers for organic materials and have enjoyed considerable commercial success.
Such hindered amine light stabilizers are described in detail by H. J. Heller and H. R. Blattmann, Pure and Applied Chemistry, 36, 141-161 (1973).
It is known that bistetramethylpiperidin-4-yl sebacate improves very much the stability to light of polypropylene. Simple derivatives of tetramethylpiperidine are relatively volatile compounds and tend to volatilize at the processing temperature and during prolonged outdoor storage of the stabilized plastic.
In U.S. Pat. Nos. 4,210,612 and 4,294,949 homopolymeric and certain copolymeric compounds having pendant hindered amine moieties are described as useful light stabilizers. The homopolymers are those made by the free radical polymerization of acryloyl or methacryloyl derivatives of compounds containing hindered amine moieties.
Copolymers of acryloyl or methacryloyl substituted hindered amine monomers with acryloyl or methacryloyl monomers containing light absorbing moieties such as the benzophenones, benzotriazoles, .alpha.-cyanocinnamates or benzalmalonates are described in U.S. Pat. No. 4,276,401 as being useful light stabilizers for organic materials.
Polymeric derivatives, which are still well soluble in the particular plastic, but remain in the plastic on exposure to heat, provide valuable stabilizers. Examples thereof are polyureas such as described in U.S. Pat. Nos. 4,233,410 and 4,086,207, polyesters such as described in U.S. Pat. No. 4,233,412, polycarbonates such as described in U.S. Pat. No. 4,234,700 or polyamides such as described in U.S. Pat. No. 4,232,131.
The present invention relates to novel oligomeric esteramides which are useful for improving the stability to light, heat and oxidation of plastics.